Historical water-quality data for the Clark Fork (river) and the mouths of selected tributaries, western Montana

The Clark Fork, occupying a major drainage area in western Montana, leaves the state of Montana 's largest river. This report is a compilation of recent historical water-quality data collected by the U.S. Geological Survey on the Clark Fork and near the mouths of major tributaries. Included in the report are water-quality data collected during various time intervals since 1969 at 18 surface-water stations. Because of the large amount of streamflow and water-temperature data collected at these 18 stations and at other sites in the study area, the data are not included in the report. However, station numbers and corresponding periods of record are listed and the availability of the data is identified. (USGS)